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MyVisionTest News Archive

Jan 21, 2011

Neovascular AMD genetically similar to polypoidal choroidal vasculopathy in JapaneseThe genomic contribution of the ARMS2/HTRA1 region of chromosome 10q26 among Japanese patients with typical neovascular age-related macular degeneration (nAMD) (also known as typical exudative AMD) and to polypoidal choroidal vasculopathy (PCV) were very similar, according to a recent study.

Polypoidal choroidal vasculopathy (PCV) is a condition characterized by multiple, recurrent, serosanguinous pigment epithelial detachment (PED), and neurosensory retinal detachment due to leakage and/or hemorrhage from abnormal choroidal lesions. Indocyanine green angiography (ICGA) is the diagnostic tool of choice for PCV and it has demonstrated that PCV affects the choroidal vasculature, causing formation of aneurysmal polypoidal lesions. Visual loss in PCV can be secondary to exudative changes associated with the polyps or due to macular hemorrhage caused by spontaneous rupture of the abnormal vasculature. The natural history of PCV is quite variable, with around 50% of patients having stable vision, and the remaining half suffering recurrent episodes of hemorrhagic and exudative maculopathy causing visual loss. Photodynamic therapy (PDT) is the most commonly described treatment for perifoveal PCV, and studies have shown that PDT is generally effective in treating PCV.

DNA samples were prepared from 84 patients with typical nAMD, 181 patients with PCV, and 276 control participants. All of the 18 haplotype-tagging single-nucleotide polymorphisms (SNPs) derived from the HapMap data and the potential functional variant, rs11200638, which extended the ARMS2/HTRA1 region by 85.2 kb, were genotyped. Associations were tested using single-SNP and haplotype analyses.

Statistically significant associations were found for six of the 19 SNPs with both typical nAMD and PCV (P < 1 × 10(-3)), peaking at a segment containing three of the SNPs: rs3793917, rs10490924, and rs11200638 (P < 10(-7)). Six common haplotypes were inferred from the nine SNPs spanning 33 kb, which included the six SNPs associated with both phenotypes. Among the six common haplotypes, one showed a positive association with typical nAMD, and two, including the one mentioned above, were associated with PCV. In addition, they corresponded to the risk alleles rs10490924 and rs11200638.

The association pattern and haplotype estimation in the ARMS2/HTRA1 region of Japanese patients with PCV were very similar to those of Japanese patients with typical nAMD. The polymorphisms responsible for nAMD and PCV may be located in this region or in the strong linkage disequilibrium of rs10490924 and rs11200638.